1. Extraction of the ^{235}U and ^{239}Pu Antineutrino Spectra at Daya Bay
- Author
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D, Adey, F P, An, A B, Balantekin, H R, Band, M, Bishai, S, Blyth, D, Cao, G F, Cao, J, Cao, J F, Chang, Y, Chang, H S, Chen, S M, Chen, Y, Chen, Y X, Chen, J, Cheng, Z K, Cheng, J J, Cherwinka, M C, Chu, A, Chukanov, J P, Cummings, N, Dash, F S, Deng, Y Y, Ding, M V, Diwan, T, Dohnal, J, Dove, M, Dvořák, D A, Dwyer, M, Gonchar, G H, Gong, H, Gong, W Q, Gu, J Y, Guo, L, Guo, X H, Guo, Y H, Guo, Z, Guo, R W, Hackenburg, S, Hans, M, He, K M, Heeger, Y K, Heng, A, Higuera, Y K, Hor, Y B, Hsiung, B Z, Hu, J R, Hu, T, Hu, Z J, Hu, H X, Huang, X T, Huang, Y B, Huang, P, Huber, D E, Jaffe, K L, Jen, X L, Ji, X P, Ji, R A, Johnson, D, Jones, L, Kang, S H, Kettell, L W, Koerner, S, Kohn, M, Kramer, T J, Langford, J, Lee, J H C, Lee, R T, Lei, R, Leitner, J K C, Leung, C, Li, F, Li, H L, Li, Q J, Li, S, Li, S C, Li, S J, Li, W D, Li, X N, Li, X Q, Li, Y F, Li, Z B, Li, H, Liang, C J, Lin, G L, Lin, S, Lin, J J, Ling, J M, Link, L, Littenberg, B R, Littlejohn, J C, Liu, J L, Liu, Y, Liu, Y H, Liu, C, Lu, H Q, Lu, J S, Lu, K B, Luk, X B, Ma, X Y, Ma, Y Q, Ma, C, Marshall, D A, Martinez Caicedo, K T, McDonald, R D, McKeown, I, Mitchell, L, Mora Lepin, J, Napolitano, D, Naumov, E, Naumova, J P, Ochoa-Ricoux, A, Olshevskiy, H-R, Pan, J, Park, S, Patton, V, Pec, J C, Peng, L, Pinsky, C S J, Pun, F Z, Qi, M, Qi, X, Qian, N, Raper, J, Ren, R, Rosero, B, Roskovec, X C, Ruan, H, Steiner, J L, Sun, K, Treskov, W-H, Tse, C E, Tull, B, Viren, V, Vorobel, C H, Wang, J, Wang, M, Wang, N Y, Wang, R G, Wang, W, Wang, X, Wang, Y, Wang, Y F, Wang, Z, Wang, Z M, Wang, H Y, Wei, L H, Wei, L J, Wen, K, Whisnant, C G, White, H L H, Wong, S C F, Wong, E, Worcester, Q, Wu, W J, Wu, D M, Xia, Z Z, Xing, J L, Xu, T, Xue, C G, Yang, L, Yang, M S, Yang, Y Z, Yang, M, Ye, M, Yeh, B L, Young, H Z, Yu, Z Y, Yu, B B, Yue, S, Zeng, Y, Zeng, L, Zhan, C, Zhang, C C, Zhang, F Y, Zhang, H H, Zhang, J W, Zhang, Q M, Zhang, R, Zhang, X F, Zhang, X T, Zhang, Y M, Zhang, Y X, Zhang, Y Y, Zhang, Z J, Zhang, Z P, Zhang, Z Y, Zhang, J, Zhao, L, Zhou, H L, Zhuang, and J H, Zou
- Abstract
This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.
- Published
- 2019